Estimating the need for radiotherapy for lung cancer: An evidence-based, epidemiologic approach

Background and Objectives: Current estimates of the proportion of cancer pa tients who will require radiotherapy (RT) are based almost entirely on expe rt opinion. The objective of this study was to use an evidence-based approa ch to estimate the proportion of incident cases of lung canter that will re quire RT at any point in the evolution of the illness. Methods: A systematic review of the literature was undertaken to identify i ndications for RT for lung cancer, and to ascertain the level of evidence t hat supported each indication. An epidemiologic approach was then used to e stimate the incidence of each indication for RT in a typical North American population of lung cancer patients. The effect of sampling error on the es timated appropriate rate of RT was calculated mathematically, and the effec t of systematic error, was estimated by sensitivity analysis, Results: It was shown that 53.6% +/- 3.3% of small-cell lung canter (SCLC) cases develop one or more indications for RT at some point in the course of the illness, 45.4% +/- 4.3% in their initial treatment, and 8.2% +/- 1.5% later for recurrence of progression, Overall, 64.3% +/- 4.7% of non-small-c ell lung cancer (NSCLC) cases require RT, 45.9% +/- 4.3% in their initial t reatment, and 18.3% +/- 1.8% later in the course of the illness. The propor tion of NSCLC cases that ever require RT is stage dependent; 41.0% +/- 5.5% in Stage I; 54.5% +/- 6.5% in Stage II; 83.5% +/- 10.6% in Stage III; and 65.7% +/- 7.6% in Stage IV. In total, 61.0% +/- 3.9% of all patients with l ung cancer will develop one or more indications for RT at some point in the illness, 44.6% +/- 3.6% in their initial treatment, and 16.5% +/- 1.5% lat er for recurrence or progression. Conclusion: This method provides a rational starting point for the long-ter m planning of radiation services, and for the audit of access to RT at the population level. We now plan to extend this study to the other major cance r sites to enable us to estimate the appropriate RT treatment rate for the cancer population as a whole, (C) 2001 Elsevier Science Inc.